Product and Software: This article applies to all Aruba controllers and ArubaOS 6.0 and later.
ArubaOS support of STP:
- Pre-3.4: STP IEEE802.1D
- 3.4 and later: Rapid Spanning Tree (RSTP) IEEE802.1w
- 6.0 and later: RSTP and PVST+
PVST+:
- Per VLAN spanning tree plus
- Cisco proprietary
- Works on 802.1q links
- PVST+ maintains a spanning tree instance for each VLAN, which treats each VLAN as a separate network
- Ability to load balance traffic
How to Configure PVST+
1) Configure STP mode to be rapid PVST:
(Aruba3200) (config) #spanning-tree mode ?
rapid Enable Rapid Spanning Tree Protocol (802.1w)
rapid-pvst Per vlan rapid spanning tree mode
(Aruba3200) (config) #spanning-tree mode rapid-pvst
This enables PVST+ globally.
2) Enable STP on the VLANs:
(Aruba3200) (config) #spanning-tree vlan ?
<vlanId> Spanning tree vlan instance
range Range of vlans
(Aruba3200) (config) #spanning-tree vlan 20
(Aruba3200) (config) #spanning-tree vlan range 20-30
This enables STP on the VLANs that want to participate in STP.
"Show" Commands Used for Debugging
Display in paragraph form the topology change counters:
show spanning-tree
show spanning-tree vlan 20
Display in tabular form the stp state for every port:
show spantree, show spantree vlan 20
Display in tabular form the ports that are forwarding traffic.
show datapath vlan-mcast
(Aruba651) #show spanning-tree
Spanning Tree instance for vlan 20 -------- STP instance
Spanning Tree is executing the IEEE compatible Rapid Spanning Tree protocol
Bridge Identifier has priority 32768, address 00:0b:86:64:32:70 ------------- Its own bridgeID
Configured hello time 2, max age 20, forward delay 15 --- Timer values
Current root has priority 32768, address 00:0b:86:61:38:10 -------------- Root bridge bridgeID
Topology change flag is set , detected flag not set , changes 4 --------------- Topology change counters
Times: hold 1, topology change 35 hello 2, max age 20, forward delay 15
Timers: hello 1, notification 0
Last topology change: 0 days, 0 hours, 0 mins, 3 secs
Spanning Tree instance for vlan 21
Spanning Tree is executing the IEEE compatible Rapid Spanning Tree protocol
Bridge Identifier has priority 32768, address 00:0b:86:64:32:70
Configured hello time 2, max age 20, forward delay 15
We are the root of the spanning tree
Topology change flag is not set , detected flag not set , changes 0
Times: hold 1, topology change 35 hello 2, max age 20, forward delay 15
Timers: hello 1, notification 0
Last topology change: 6 days, 22 hours, 43 mins, 53 secs
(Aruba651) #show spanning-tree vlan 20
Spanning Tree instance for vlan 20
Spanning Tree is executing the IEEE compatible Rapid Spanning Tree protocol
Bridge Identifier has priority 32768, address 00:0b:86:64:32:70
Configured hello time 2, max age 20, forward delay 15
We are the root of the spanning tree
Topology change flag is not set , detected flag not set , changes 5
Times: hold 1, topology change 35 hello 2, max age 20, forward delay 15
Timers: hello 1, notification 0
Last topology change: 0 days, 0 hours, 18 mins, 17 secs
(Aruba651) # show spantree
Spanning tree instance vlan 20 ----------- STP instance
Designated Root MAC 00:0b:86:61:38:10 ----------- Root bridge MAC
Designated Root Priority 32768 ----------- Root bridge priority
Root Cost 4
Root Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec
Bridge MAC 00:0b:86:64:32:70 ----------- Own MAC
Bridge Priority 32768 ------------> Own priority
Configured Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec
Rapid Spanning Tree port configuration
--------------------------------------
Port State Cost Prio PortFast P-to-P Role
---- ----- ---- ---- -------- ------ ----
GE 1/0 Off 4 128 Disable Enable Disabled
GE 1/1 Forwarding 4 128 Disable Enable Root
GE 1/2 Discarding 4 128 Disable Enable Alternate
GE 1/3 Off 100 128 Disable Enable Disabled
GE 1/4 Discarding 4 128 Disable Enable Disabled
GE 1/5 Discarding 4 128 Disable Enable Disabled
GE 1/6 Discarding 4 128 Disable Enable Disabled
GE 1/7 Discarding 4 128 Disable Enable Disabled
Pc 0 Discarding 100 128 Disable Enable Disabled
Pc 1 Discarding 100 128 Disable Enable Disabled
Pc 2 Discarding 100 128 Disable Enable Disabled
Pc 3 Discarding 100 128 Disable Enable Disabled
Pc 4 Discarding 100 128 Disable Enable Disabled
Pc 5 Discarding 100 128 Disable Enable Disabled
Pc 6 Discarding 100 128 Disable Enable Disabled
Pc 7 Discarding 100 128 Disable Enable Disabled